about passive voice

[ivygreen]

Please teach me about the senteces below.
(Change the active voice sentence into the passive voice)

"Who invented the airplane?" --

"Who was the airplane (invented)(by)?"

Why "who" can be used in this passive voice sentence?

Is it because "who" comes the first as the subject?

[mykwyner]

In a passive voice sentence, the object becomes the subject and the subject becomes the object of a prepositional phrase.

The boy [subject] saw [verb] the dog [object]. Active voice

The dog [new subject] was seen [passive verb phrase] by [preposition] the boy [object of the preposition]. Passive voice

Your sentence, "Who was the airplane invented by?" ends with an unattached preposition and is considered less than correct. In the passive voice, that sentence should be, "By whom was the airplane invented?" or, "The airplane was invented by whom?" The fact that these sentences sound awkward and stilted is reason enough to not use the passive voice in constructions such as these.

[ivygreen]

Dear mykwyner,

Thank you very much for your lucid explanation.